[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

We discuss a phase space representation of quantum dynamics of systems with many degrees of freedom. This representation is based on a perturbative expansion in quantum fluctuations around one of the classical limits. We explicitly analyze expansions around three such limits: (i) corpuscular or Newtonian limit in the coordinate-momentum representation, (ii) wave or Gross-Pitaevskii limit for interacting bosons in the coherent state representation, and (iii) Bloch limit for the spin systems. We discuss both the semiclassical (truncated Wigner) approximation and further quantum corrections appearing in the form of either stochastic quantum jumps along the classical trajectories or the nonlinear response to such jumps. We also discuss how quantum jumps naturally emerge in the analysis of non-equal time correlation functions. This representation of quantum dynamics is closely related to the phase space methods based on the Wigner-Weyl quantization and to the Keldysh technique. We show how such concepts as the Wigner function, Weyl symbol, Moyal product, Bopp operators, and others automatically emerge from the Feynmann's path integral representation of the evolution in the Heisenberg representation. We illustrate the applicability of this expansion with various examples mostly in the context of cold atom systems including sine-Gordon model, one- and two-dimensional Bose Hubbard model, Dicke model and others.

Phase space representation of quantum dynamics

Catalytic effects of nano additives on decomposition and combustion of RDX-, HMX-, and AP-based energetic compositions

Synthesis of CuO nanorods and their catalytic activity in the thermal decomposition of ammonium perchlorate

The high-spin states of 112In have been investigated with in-beam \( \gamma\) -ray spectroscopic methods using the 110Pd (7Li, 5n)112In reaction at a beam energy of 50MeV. A level scheme with 3 band structures has been established. The backbending associated with the alignment of a pair of g7/2/d5/2 neutrons has been found in the negative-parity yrast band. The configuration for the positive-parity yrare band has been assigned to \( \pi\)g9/2 ⊗ \( \nu\)g7/2 for the lower-spin states, and \( \pi\)g9/2 ⊗ \( \nu\)h211/2(g7/2) for the higher-spin levels.

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High-spin yrast and yrare structures in 112In

CuO nanocrystals of different surface areas were prepared. All samples were characterized by X-ray diffraction, transition electron microscope, thermogravimetry, Brunauer-Emmett-Teller technique, Fourier transform infrared spectroscopy, and Raman spectroscopy. CuO nanocrystals showed a stable monoclinic structure. With increasing surface areas, the surface hydration became significant, which is followed by shifts in infrared frequencies and Raman phonon modes. CuO nanocrystals were explored as an additive to catalytic decomposition of ammonium perchlorate (AP). AP decomposition underwent a two-stage process. Addition of CuO nanocrystals led to a downshift of high-temperature stage towards lower temperatures.

CuO nanocrystals in thermal decomposition of ammonium perchlorate

Resveratrol Ameliorated Vascular Calcification by Regulating Sirt-1 and Nrf2

This work reported on the thermal decomposition of ammonium perchlorate activated by addition of NiO nanocrystals with different surface areas. NiO samples were characterized by X-ray diffraction (XRD), transition electron microscope (TEM), Brunauer-Emmett-Teller (BET) technique, Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. With increasing annealing temperature, the surface areas of NiO samples reduced from 108.6 to 0.9 m2 g−1. The catalytic activities of NiO nanocrystals on the thermal decomposition of ammonium perchlorate were investigated by thermogravimetric analysis (TG) coupled with differential thermal analysis (DTA). With addition of NiO nanocrystals, thermal decomposition temperature of AP decreased greatly. Larger surface areas of NiO nanocrystals promoted the thermal decomposition of AP.

THERMAL DECOMPOSITION OF AMMONIUM PERCHLORATE ACTIVATED VIA ADDITION OF NiO NANOCRYSTALS

A gas-filled recoil separator, SHANS (Spectrometer for Heavy Atom and Nuclear Structure), constructed at the Institute of Modern Physics in Lanzhou is reported. With the QDQQ magnetic configuration, where D and Q denote the dipole and quadrupole magnets respectively, the apparatus is used to study the heavy nuclei produced in the heavy-ion-induced fusion reactions. The helium gas is filled in the field region of the separator at a pressure of about 1 mbar. The maximum magnetic rigidity of the dipole magnet is 2.9 Tm. With the commissioning of the device, the performance of the separator in several fusion evaporation reactions is investigated.

Guangsheng Li

Papers

High-spin yrast and yrare structures in 112In

CuO nanocrystals in thermal decomposition of ammonium perchlorate

Resveratrol Ameliorated Vascular Calcification by Regulating Sirt-1 and Nrf2

THERMAL DECOMPOSITION OF AMMONIUM PERCHLORATE ACTIVATED VIA ADDITION OF NiO NANOCRYSTALS

A gas-filled recoil separator, SHANS